36 GENERAL HISTORY OF 



elation in 1834. The following is Ehrenberg^s account 

 of it : — " If a solution of the chloride of aluminum be 

 dropped into a solution of potassa^ by the attenuate 

 precipitation and solution of the aluminum in the excess 

 of alkahj an appearance will be given to the drop of 

 aluminated matter, by the chemical changes and re- 

 actions which take place^ as if the Amoeba diffluens (see 

 description, Part II.) were actuallypresent, both as to 

 its form and evolutions, and it will seem to be alive. 

 Such appearance is considered, by its able discoverer^ 

 as bearing the same relationship to the real animalcule 

 as a doll or a figure moved by mechanism does to a living 

 child.'^ 



Section XI. — On the Evolution of Light by Infusoria, 



Several small animals are known to emit light, appa- 

 rently phosphorescent, as the female glow-worm, and 

 some species of the ^liriapoda, which I have frequently 

 noticed in the gravel walks of a garden, on a dark autum- 

 nal evening. This emission of light, whether in the 

 above-named animals, or in Infusoria, is evidently the 

 result of a vital process. In the latter class of creatures, 

 it seems like a single spark, of a moment's duration, but 

 capable of being repeated at sliort intervals. That this 

 light is electrical, analogy \a ould lead us to infer; as 

 experiments made upon larger creatures have proved it to 

 be such with them. 



The phosphorescence of the sea is produced by Infu- 

 soria, chiefly belonging to the family Cyclidina ; and when 



